Sahih al-Bukhari 2551
صحيح البخاري#2551SahihNarrated Abu Musa:The Prophet (ﷺ) said, "The Mamluk (slave) who worships his Lord in a perfect manner, and is dutiful, sincere and obedient to his Saiyid (master), will get a double reward
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 49:34